JPH04257814A - Lens position controller for interchangeable lens correspondence type camera - Google Patents

Abstract

PURPOSE:To provide a lens controller for an interchangeable lens correspondence type camera, which quickly can focus after a lens unit is attached, in the case the lens unit is attached to a camera unit in a state where a zoom lens enters a widemacro region. CONSTITUTION:When the lens unit 2 is attached to the camera unit 3 in the state where the zoom lens 7 is positioned at the widemacro region, and further, a focus mode stored in the above-mentioned camera unit 3 before the lens unit 2 is attached, is an auto focus mode, a driving/commanding signal is outputted to a zoom lens driving means 14 by a driving/commanding signal output means 25, and the zoom lens 7 is moved to a prescribed position out of the above-mentioned widemacro region.

Description

[Detailed description of the invention]

0001

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a lens control device for a camera compatible with interchangeable lenses, which is applied to, for example, a video camera. The present invention relates to a lens control device for an interchangeable lens compatible camera that controls a lens unit when the camera is attached to a camera.

0002

[Background Art] In recent years, the spread of video equipment such as video cameras has been remarkable.
It is designed to be smaller and lighter, and to improve operability.

[0003] In recent years, video cameras have also been developed into interchangeable lens systems in which a lens unit is removably connected to a camera unit, as part of efforts to increase the number of functions, improve operability, and improve performance.

Furthermore, many lens units having a macro photography (close-up photography) function have been proposed. To give an example of these, for example, focusing is performed with the focus lens (front lens) of the first group, and zooming is performed with the zoom lenses of the second and third groups.

[0005] In such a lens unit, when the distance of the subject is close and exceeds the distance range (normal range) in which the focus can be adjusted by the first group focus lens, the focus lens cannot adjust the focus. , macro photography is performed by relatively moving the second group and third group zoom lenses that perform zooming.

[0006]

[Problems to be Solved by the Invention] However, according to conventional video cameras, if the lens unit is attached to the camera unit while its zoom lens is positioned in the wide macro area, the focus adjustment after the lens unit is attached is difficult. There were cases where it did not work properly. For example, the problem is that the focus lens is slow to focus.

[0007] This is because the subject to be focused on immediately after attaching the lens unit is generally in the normal area, so if the zoom lens is in the wide macro area, the zoom lens will not move within the wide macro area. After searching and determining that there is no subject within this wide macro area, stop the zoom lens at a predetermined position in the normal area, and
This is because the autofocus operation is performed with the focus lens, so the wide macro area search time is added to the focusing time.

The present invention has been made in view of the above-mentioned circumstances, and provides for quick focusing after the lens unit is attached when the lens unit is attached to the camera unit while the zoom lens remains in the wide macro area. It is an object of the present invention to provide a lens control device for a camera compatible with interchangeable lenses.

[0009]

[Means for Solving the Problems] In order to achieve the above object, the present invention provides a focus lens drive means for moving a focus lens to perform focus adjustment, and a zoom lens drive means for moving a zoom lens to perform a zooming operation. and a zoom lens position detection means for detecting a moving position of the zoom lens, the lens unit is a lens control device for an interchangeable lens compatible camera that is detachably attached to a camera unit. When attached to the camera unit, the focus mode stored in the camera unit before the lens unit is attached is an autofocus mode, and the zoom lens is located in a wide macro area according to the zoom lens position detection means. further comprising drive command signal output means for outputting a drive command signal for moving the zoom lens to a predetermined position outside the wide macro area to the zoom lens drive means when the zoom lens is detected, before starting an autofocus mode operation. It is characterized by:

0010

[Operation] When a lens unit is attached to a camera unit, the focus mode stored in the camera unit before this lens unit is attached is autofocus mode, and the zoom lens position detection means indicates that the zoom lens is When it is detected that the zoom lens is in the wide macro area, the drive command signal output means outputs a drive command signal to the zoom lens driving means to move the zoom lens to a predetermined position outside the wide macro area. The lens moves out of the wide macro area. This makes it possible to significantly shorten the focusing time in autofocus mode after replacing the lens unit while the zoom lens remains in the wide macro range.

[0011]

DESCRIPTION OF THE PREFERRED EMBODIMENTS An embodiment of the present invention will be described below in detail with reference to the drawings.

FIG. 1 is a block configuration diagram of an interchangeable lens compatible video camera to which a lens control device according to the present invention is applied. In the figure, 1 is an interchangeable lens compatible video camera, which includes a lens unit 2 and a camera unit. It consists of 3. The lens unit 2 and camera unit 3 are detachably connected by a mount 4, and when connected, various communications such as initialization information and control information are transmitted through electrical contacts provided on the mount 4. A signal transmission line 5 is formed for this purpose.

Inside the lens unit 2, a lens group consisting of a focus lens 6 for adjusting focus, a zoom lens 7 for zooming with variable magnification, an aperture 8, a relay lens 9, etc. is arranged. and motors 10 and 11 for driving the focus lens 6, zoom lens 7, and aperture 8, respectively.
, 12, and drive circuits (drive means) 13, 14, and 15, respectively. These motors 10 to 12 and drive circuits 13 to 15 are connected to a control microcomputer 16 that controls all the controls on the lens unit 2 side.
The drive is controlled based on control information supplied from the camera unit 3 via the signal transmission line 5. The operating states of the focus lens 6, zoom lens 7, and diaphragm 8 are determined by a focus encoder 17, respectively.
, zoom encoder (zoom lens position detection means) 18
, and the aperture encoder 19, and is taken into the microcomputer 16 on the lens unit 2 side, and after performing predetermined processing as necessary, is sent to the microcomputer 16 on the camera unit 3 side via the signal transmission line 5, which will be described later. It is transmitted to computer 25.

On the other hand, within the camera unit 3, there is a C, for example, for photoelectrically converting the subject image formed by the lens unit 2 connected thereto into a video signal.
an image sensor 20 such as a CD; a preamplifier 21 that amplifies the video signal output from the image sensor 20 to a predetermined level;
A signal processing circuit 22 performs predetermined processing such as predetermined gamma correction, blanking processing, and addition of a synchronization signal to the output of the preamplifier 21, converts it into a standardized television signal, and outputs it. The AF circuit 23 detects the focus state based on the high frequency component of the luminance signal, compares the average value of the luminance signal level of the video signal with a preset reference level, and adjusts the aperture so that the luminance signal level is always equal to the reference level. AE circuit 24 that outputs signals for controlling the zoom lens 8, a control microcomputer (drive command signal output means) 25 that controls and controls all functions of the camera unit 3, and commands for operating the zoom lens 7. A zoom switch 26 for generating an auto-zoom mode, an AZ mode setting switch 27 for setting an auto-zoom mode, an AF mode setting switch 28 for setting an auto-focus mode, and the like are provided.

A focus state detection signal outputted from the AF circuit 23, an aperture state detection signal outputted from the AE circuit 24,
Operation signals for each of the zoom switch 26, AZ mode setting switch 27, and AF mode setting switch 28 are sent to the microcomputer 25 on the camera unit 3 side.
is supplied to the microcomputer 16 on the lens unit 2 side, performs predetermined calculations while referring to the operating status information returned from the microcomputer 16 on the lens unit 2 side, and converts it into a format to be supplied to the microcomputer 16 on the lens unit 2 side. After that, it is transmitted to the microcomputer 16 on the lens unit 2 side via the signal transmission line 5,
Each part on this lens unit 2 side is controlled.

The AF circuit 23 includes a high pass filter (HP
F) 231, detection circuit 232, peak hold circuit 23
3 and an A/D conversion circuit 234. and,
This AF circuit 23 passes through a high-pass filter 231 the high-frequency component of the luminance signal in the video signal that changes depending on the focusing state.
The detection circuit 232 detects this and converts it to a DC level, the peak hold circuit 233 detects the peak value at predetermined intervals, and the A/D conversion circuit 234
After converting it into a digital signal, it is supplied to the microcomputer 25 on the camera unit 3 side. The microcomputer 25 on the camera unit 3 side detects the peak value of the high frequency component at predetermined intervals, and sends control information to the microcomputer 25 on the lens unit 2 side to drive the focus lens 6 in the direction where the peak value is maximized. Calculations are made with reference to the aperture information from the computer 16, taking into account the depth of field, and output to the microcomputer 16 on the lens unit 2 side.

The AE circuit 24 also includes an integrating circuit 241,
It has a comparison circuit 242 and an A/D conversion circuit 243. The AE circuit then uses an integration circuit 241 to integrate the luminance signal component separated by YC using a low-pass filter or the like in the signal processing circuit, and compares the light amount information with a preset reference amount level in the comparison circuit 242. The A/D conversion circuit 243 converts information on the difference into a digital signal and supplies it to the microcomputer 25 on the camera unit 3 side. Generates a control signal to drive the On the lens unit 2 side, based on the control signal, a drive signal is output from the microcomputer 16 to the aperture drive circuit 15 in the lens unit 2,
The diaphragm 8 is driven and controlled by this diaphragm drive circuit 15 . As a result, the amount of light input to the camera unit 3 side changes, and a control loop is formed so that an appropriate aperture value is finally achieved.

The AZ mode is set by operating the AZ mode setting switch 27, and changes in subject distance are corrected by varying the magnification to keep the angle of view constant. etc., when the subject distance changes, the microcomputer 25 on the camera unit 3 side changes the zoom encoder information, that is, the focal length information, and the focus encoder information, that is, the subject distance, supplied from the microcomputer 16 on the lens unit 2 side. Based on the information, the change in the subject distance is determined, and the magnification for correcting the change in the angle of view due to the change in the subject distance, that is, the control information for the zoom lens 7, is calculated, and this is calculated by the microcontroller on the lens unit 2 side. Transmit to computer 16. Then, on the lens unit 2 side, a drive command signal is output from the microcomputer 16 to the zoom lens drive circuit 14 based on this transmitted information, and the zoom lens drive circuit 1
4, the zoom lens 7 is drive-controlled so as to keep the angle of view of the subject constant within the image pickup screen. In addition, Figure 1
Inside, 29 is a video signal output terminal.

Now, in FIG. 1, the lens unit 2
Consider the case where the camera unit 3 is attached to the camera unit 3. When the lens unit 2 is attached to the camera unit 3, the camera unit 3 first refers to the focus mode stored in the microcomputer 25 on the camera unit 3 side before the lens unit was attached.

Then, the microcomputer 25 on the camera unit 3 side inputs predetermined initial information to the lens unit 2.
The signal is obtained from the side microcomputer 16 via the signal transmission line 5. After that, actual control is started, and the zoom encoder information obtained by the microcomputer 25 on the camera unit 3 side via the signal transmission line 5,
That is, if the position information of the zoom lens 7 indicates the wide macro area, this means that the lens unit 2 is attached to the camera unit 3 with the zoom lens 7 still stopped in the wide macro area. At this time, if the focus mode stored before the lens unit 2 was attached was the autofocus mode, the microcomputer 25 on the camera unit 3 side automatically zooms the lens unit 2 before starting the autofocus mode operation. A drive command signal is applied to the lens drive circuit 14 via the signal transmission line 5 until the zoom encoder information no longer indicates a wide macro area.

The internal processing of the microcomputer 25 on the camera unit 3 side at this time will be explained in detail using the flowchart shown in FIG.

FIG. 2 shows a routine that is processed immediately before the communication between the microcomputers 16 and 25 of the lens unit 2 and camera unit 3 ends and the autofocus mode routine is entered.

First, in step S1, the lens unit 2
After the camera unit 3 is attached to the camera unit 3, it is determined whether or not the processing of this routine has been completed. If it has finished, exit from this routine without doing anything. Further, if the processing of this routine has not been completed, in step S2, the content of the RAM (random access memory), which is a storage means that stores the focus mode state of the camera unit 3 side, is referred to and 2) is the autofocus mode or not. If it is not the autofocus mode, the process proceeds to step S4, sets the routine end flag, and exits the routine. Further, if the previous focus mode is the autofocus mode, the process proceeds to step S3, and it is determined whether the zoom encoder information obtained through communication with the microcomputer 16 on the lens unit 2 side is within the wide macro area. , if it is not within the wide macro area, step S4 is executed and the routine exits. If the zoom encoder information is within the wide macro area, the process proceeds to step S5, where the zoom lens driving circuit 14 moves the zoom lens 6 to a predetermined position outside the wide macro area, for example, to the closest end of the normal area. Outputs a drive command signal.

By placing the above processing routine immediately before the autofocus mode routine, the control operation of the apparatus of the present invention is executed.

[0025] In the above embodiment, a case was described in which the lens control device of the present invention is applied to a video camera, but the invention is not limited to this, and an interchangeable lens compatible type in which a lens unit is detachably connected to a camera unit is described. It is widely applicable to cameras.

[0026]

As described above, according to the lens control device for an interchangeable lens compatible camera according to the present invention, when the lens unit is attached to the camera unit with its zoom lens in the wide macro area, Before starting autofocus mode operation, by moving the zoom lens to a predetermined position outside the wide macro area, that is, to the normal area, the autofocus mode will be in the normal area, so the focusing time in autofocus mode will be significantly reduced. be shortened.

[Brief explanation of the drawing]

FIG. 1 is a block configuration diagram of an interchangeable lens compatible camera to which a lens control device according to an embodiment of the present invention is applied.

FIG. 2 is a flowchart for explaining control operations of a lens control device according to an embodiment of the present invention.

[Explanation of symbols]

1 Video camera (interchangeable lens compatible camera) 2
Lens unit 3 Camera unit 6 Focus lens 7 Zoom lens

Claims (1)

[Claims] 1. Focus lens driving means for adjusting focus by moving a focus lens; zoom lens driving means for performing zooming operation by moving a zoom lens; and a zoom lens position for detecting a moving position of the zoom lens. A lens control device for an interchangeable lens compatible camera in which a lens unit including a detection means is detachably attached to a camera unit, wherein when the lens unit is attached to the camera unit, before the lens unit is attached. When the focus mode stored in the camera unit is autofocus mode and the zoom lens position detection means detects that the zoom lens is in a wide macro area, before starting the autofocus mode operation, A lens control device for an interchangeable lens compatible camera, comprising drive command signal output means for outputting a drive command signal for moving the zoom lens to a predetermined position outside the wide macro area to the zoom lens drive means.